8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/722.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/244.(1/1*4)+(1/4*7)+(1/7*10)+(1/
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![8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/722.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/244.(1/1*4)+(1/4*7)+(1/7*10)+(1/](/uploads/image/z/11955479-23-9.jpg?t=8%E9%A2%98%E5%88%86%E6%95%B0%E7%9A%84%E8%AE%A1%E7%AE%97.1.7%E5%8F%885%2F6-6%E5%8F%887%2F12%2B5%E5%8F%889%2F20-4%E5%8F%8811%2F30%2B3%E5%8F%8813%2F42-2%E5%8F%8815%2F56%2B1%E5%8F%8817%2F722.1%2B%EF%BC%881%2F1%2B2%EF%BC%89%2B%EF%BC%881%2F1%2B2%2B3%EF%BC%89%E2%80%A6%E2%80%A6%2B%EF%BC%881%2F1%2B2%2B%E2%80%A6%E2%80%A6%2B10%EF%BC%893.%E3%80%90%EF%BC%8849%2F12-63%2F20%2B77%2F30-91%2F42%2B105%2F56%EF%BC%89-3%E5%8F%881%2F6%E3%80%91%E9%99%A4%E4%BB%A51%2F244.%EF%BC%881%2F1%2A4%EF%BC%89%2B%EF%BC%881%2F4%2A7%EF%BC%89%2B%EF%BC%881%2F7%2A10%EF%BC%89%2B%EF%BC%881%2F)
8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/722.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/244.(1/1*4)+(1/4*7)+(1/7*10)+(1/
8题分数的计算.
1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/72
2.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)
3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/24
4.(1/1*4)+(1/4*7)+(1/7*10)+(1/10*13)……+(1/97*100)
5.(1994/1994平方-1993*1995)+6
6.1999*(3.4*69+3.5)/3.5*69-3.4
7.分数线上面:1.2*3.6*10.8+2*6*18+1/13*3/13*9/3下面:1.2*2.4*4.8+2*4*8+1/13*2/13*4/13
8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/722.1+(1/1+2)+(1/1+2+3)……+(1/1+2+……+10)3.【(49/12-63/20+77/30-91/42+105/56)-3又1/6】除以1/244.(1/1*4)+(1/4*7)+(1/7*10)+(1/
1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/72
=(7-6+5-4+3-2+1)+(5/6-7/12+.+17/72)
=4+(1/2+1/3-1/3-1/4+.+1/8+1/9)
=4+(1/2+1/9)
=4又11/18
3.原式=(3430/840-2640/840+2156/830-1820/840+1575/840-2660/840)*24
=41/840*24
=41/35
4.1/1*4+1/4*7+1/7*10+1/10*13+~+1/97*100
=(1/3)*[(1-1/4)+(1/4-1/7)+(1/7-1/10)+...+(1/97-1/100)]
=(1/3)*(1-1/100)
=(1/3)*(99/100)
=33/100
5.1994/(1994^2-1993*1995)+6
=1994/[1994^2-(1994-1)(1994+1)]+6
=1994/[1994^2-(1994^2-1)]+6
=1994/(1994^2-1994^2+1)+6
=1994+6
=2000
用公式:(a+b)*(a-b)=a^2-b^2
6.
原式=1999*(3.4*70+0.1)/(3.4*69+3.5)
=1999*(3.4*70+0.1)/(3.4*70+0.1)
=1999
7.
(1.2*3.6*10.8+2*6*8+1/13+3/13+9/13)/(1.2*2.4*4.8+2*4*8+1/13+2/13++4/13)
=(1.2*1.2*3*1.2*9+96+1)/(1.2*1.2*2*1.2*4+64+7/13)
=(46.656+96+1)/(13.824+64+7/13)
=75